A number of activist organizations protested the absence of women on Facebook’s board of directors before the company’s IPO. They’re taking credit for COO Sheryl Sandberg’s appointment, but say it’s not enough.

In a statement released by Facebook today, the company explained that it had finally added a woman — its COO Sheryl Sandberg — to its board. Good start, but keep going, say some who’ve long been calling for such a move.

Two groups — The California State Teachers’ Retirement System and a feminist organization called UltraViolet — have been very vocal over the past few months in trying to convince Facebook to add a woman to its board. UltraViolet, which launches campaigns to fight sexism and gender inequality across the country, circulated a petition in April demanding a woman be added to Facebook’s board, which 53,000 people signed. On April 25, they also held a small protest outside Facebook’s New York headquarters.

“The power of our campaign was that it put the problem squarely in front of Facebook before they went public,” Shaunna Thomas, a co-founder of Ultra Violet, told BuzzFeed. Thomas emphasized, however, that adding one lone woman to the board was a step forward, but not a total victory. “We take this as an opportunity to congratulate them, but also to remind them to continue to do more.” But, she added, “We in no way see this as sufficient for Facebook or any other company.” (Given the limited number of coveted spots on Facebook’s board — Sandberg is the eighth member — it’s unlikely that another woman would be added anytime soon, Thomas mentioned.)

The California State Teachers’ Retirement System (CalSTRS) was also active on the issue. With over $150 billion in assets, CalSTRS is the second-largest pension fund in the United States, and is a large shareholder in Facebook through its investments in various private equity funds. In a February letter to Facebook CEO Mark Zuckerberg, they wrote: “We are disappointed that the Facebook board will not have any women members. We believe that investors and the company would benefit from a larger, more diverse board.”

Similarly to UltraViolet, CalSTRS CEO Jack Ehnes said in a statement that he was “proud CalSTRS played a role in fostering this very positive change, but we’re not there yet.”

Ehres continued: “It’s clear the company received the message loud and clear. We are optimistic Facebook is on its way to further expanding the board while simultaneously creating the diversity and independence that we think is important to the future sustainability of this vibrant company.”